add tag assign to documents batch

src/Tag/TagService.php

@@ -110,6 +110,49 @@ final class TagService
         }
     }
 
+    // =========================================================
+    // TAG → DOCUMENT SYNC (Bulk Assign)
+    // =========================================================
+
+    /**
+     * Synchronisiert alle Dokumente eines Tags.
+     * Löst einen Rebuild aus, da document_ids Teil des NDJSON sind.
+     */
+    public function syncTagDocuments(Tag $tag, array $newDocumentIds): void
+    {
+        $newDocumentIds = array_unique($newDocumentIds);
+
+        $currentRelations = $this->em
+            ->getRepository(DocumentTag::class)
+            ->findBy(['tag' => $tag]);
+
+        $currentDocumentIds = array_map(
+            fn(DocumentTag $dt) => (string) $dt->getDocument()->getId(),
+            $currentRelations
+        );
+
+        $toAdd    = array_diff($newDocumentIds, $currentDocumentIds);
+        $toRemove = array_diff($currentDocumentIds, $newDocumentIds);
+
+        foreach ($toAdd as $documentId) {
+            $document = $this->em->getRepository(Document::class)->find($documentId);
+            if ($document instanceof Document) {
+                $this->em->persist(new DocumentTag($document, $tag));
+            }
+        }
+
+        foreach ($currentRelations as $relation) {
+            if (in_array((string) $relation->getDocument()->getId(), $toRemove, true)) {
+                $this->em->remove($relation);
+            }
+        }
+
+        if ($toAdd || $toRemove) {
+            $this->em->flush();
+            $this->triggerRebuildIfIdle();
+        }
+    }
+
     // =========================================================
     // INTERNAL HELPERS
     // =========================================================